import 'package:drift/drift.dart';
import 'package:uto_manager/infrastructure/database/app_database.dart';

part 'unit_dao.g.dart';

/// Data Access Object for [Units] table operations.
@DriftAccessor(tables: [Units])
class UnitDao extends DatabaseAccessor<AppDatabase> with _$UnitDaoMixin {
  UnitDao(super.db);

  /// Returns all unit rows.
  Future<List<Unit>> getAllUnits() => select(units).get();

  /// Returns the unit with [unitId], or null if not found.
  Future<Unit?> getUnitById(String unitId) =>
      (select(units)..where((t) => t.unitId.equals(unitId))).getSingleOrNull();

  /// Returns all direct children of [parentUnitId].
  Future<List<Unit>> getChildren(String parentUnitId) =>
      (select(units)..where((t) => t.parentUnitId.equals(parentUnitId))).get();

  /// Returns all root units (no parent).
  Future<List<Unit>> getRoots() => (select(units)..where((t) => t.parentUnitId.isNull())).get();

  /// Returns all units at the given [echelon] string value.
  Future<List<Unit>> getByEchelon(String echelon) =>
      (select(units)..where((t) => t.echelon.equals(echelon))).get();

  /// Inserts a new unit row. Throws on duplicate primary key.
  Future<void> insertUnit(UnitsCompanion entry) =>
      into(units).insert(entry, mode: InsertMode.insertOrFail);

  /// Inserts multiple unit rows in a single transaction.
  Future<void> insertAllUnits(List<UnitsCompanion> entries) =>
      batch((b) => b.insertAll(units, entries, mode: InsertMode.insertOrFail));

  /// Updates an existing unit row.
  Future<bool> updateUnit(UnitsCompanion entry) => update(units).replace(entry);

  /// Deletes the unit with [unitId].
  Future<int> deleteUnit(String unitId) =>
      (delete(units)..where((t) => t.unitId.equals(unitId))).go();

  /// Deletes all units.
  Future<int> deleteAllUnits() => delete(units).go();

  /// Returns a stream that emits all units whenever the table changes.
  Stream<List<Unit>> watchAllUnits() => select(units).watch();

  /// Returns a stream that emits children of [parentUnitId] on changes.
  Stream<List<Unit>> watchChildren(String parentUnitId) =>
      (select(units)..where((t) => t.parentUnitId.equals(parentUnitId))).watch();
}